Although raised in a prosperous and prestigious African-American home in Tuskegee, Ala., Sammy Younge found himself drawn most to the civil rights movement. While the cause cost him his life, his actions and determination helped to transform this Southern city.

One of the earliest assaults on segregated transit in the South occurred in Louisville, Ky., in 1870-71. There, the city’s black community organized a successful protest that relied on nonviolent direct action, a tactic that would give shape to the modern civil rights movement nearly a century later.

In Boston, widely regarded as the center of the abolitionist movement, black leaders called on citizens to resist the newly passed Fugitive Slave Law in 1850 in order “to make Massachusetts a battlefield in defense of liberty.”